POS0526 HIGH-RESOLUTION PERIPHERAL QUANTITATIVE COMPUTED TOMOGRAPHY AND PREDICTION OF EROSIVE PROGRESSION AS ASSESSED BY THE GOLD STANDARD CONVENTIONAL RADIOGRAPHY IN ESTABLISHED RHEUMATOID ARTHRITIS: A 1-YEAR COHORT STUDY
Authors: J. Therkildsen, R. Klose-Jensen, A. B. Blavnsfeldt, B. Langdahl, A. Zejden, J. Thygesen, K. Keller, E. M. Hauge
Journal: Annals of the Rheumatic Diseases (2022)

Background High-Resolution peripheral Quantitative Computed Tomography (HR-pQCT) is a promising imaging technique for assessing erosive disease in rheumatoid arthritis (RA). We have shown that the diagnostic accuracy in detecting erosive disease of HR-pQCT of two joints corresponds to conventional radiography (CR) of 44 joints in established RA (1). No data assessing HR-pQCT as a tool for predicting erosive radiographic progression in a large cohort of established RA has been published. Objectives To assess the association between erosive disease identified using either CR or HR-pQCT at baseline and erosive progression using CR during 1-year follow-up in established RA. Methods This observational cohort study included 220 patients with RA (disease duration ≥ 5 yrs) at the Department of Rheumatology, Aarhus University Hospital, between Mar. 2018 and Oct. 2020. All participants had demographic information collected, together with HR-pQCT at baseline and CR made at baseline and 1-year follow-up. Erosive assessment using HR-pQCT was performed at the second and third metacarpophalangeal (MCP) joint (2). The Sharp/van der Heijde score (SHS) method was used to assess erosive status and erosive progression using CR of hands, wrists and feet (3). Results In total, 220 participants with RA (median age 66 yrs, interquartile range (IQR) 57-72; 71% women) were included and 212 completed their follow-up visit in Dec. 2021 (dropout n=8 (4 %)). During follow-up (median 1 yrs, range 0.7-1.4), erosive progression on CR was detected in 24 of 211 (11%) (missing baseline CR, n=1). Characteristics of the study population by erosive progression are shown in Table 1. In unadjusted regression analyses, number of erosions on HR-pQCT at baseline and erosion score (per 10) using CR at baseline were associated with erosive progression (yes/no) on CR at 1-year (Odds ratio (OR) 1.1; 95%CI 1.0-1.1; p&lt;.05 and OR 1.1; 95%CI 1.0-1.2; p&lt;.01 ). After adjusting for age and sex, erosion score remained associated with erosive progression (OR 1.1; 95%CI 1.1-1.2; p&lt;.01 ), but number of erosions did not (OR 1.0; 95%CI 1.0-1.1; p=.07 ). Table 1. Demographics at baseline Progression on CR No progression on CR P value No 24/211 (11) 187/211 (89) Age, yrs 66 (57-73) 66 (57-71) .80 Women 15/24 (63) 134/187 (72) .35 Disease Duration, yrs 20 (8-28) 15 (9-23) .44 DAS28-CRP 1.7 (1.5-2.5) 1.8 (1.5-2.5) .53 Erosive on CR 24/24 (100) 141/187 (75) &lt; .01 Erosive 2 nd /3 rd MCP on CR * 17/23 (74) 62/185 (34) &lt; .001 Erosive on HR-pQCT 22/23 (96) 153/185 (83) .14 Erosion score (per 10 ) 4 (2-7) 1 (0-3) &lt; .0001 Erosion number 10 (5-17) 3 (1-10) &lt; .01 Total erosion volume, mm 3 128 (19-201) 26 (2-111) &lt; .05 Data are no. (%) or median with interquartile range. P-values: Mann-Whitney U or Fisher’s exact test. Missing HR-pQCT, n=3. CR = conventional radiography, DAS28-CRP = disease activity score of 28 joints based on C-reactive protein, HR-pQCT = high-resolution peripheral quantitative computed tomography * Same hand as HR-pQCT scanned Conclusion In established RA, baseline CR of 44 joints is superior to baseline HR-pQCT of two joints in identifying individuals at risk of erosive progression on CR. This underlines the need for a head-to-head comparison between progression identified by HR-pQCT and CR to fully assess the clinical utility of HR-pQCT in predicting erosive progression compared to CR. References [1]Klose-Jensen R, Therkildsen J, Blavnsfeldt AG, et al. Diagnostic accuracy of high-resolution peripheral quantitative computed tomography and X-ray for classifying erosive rheumatoid arthritis. Rheumatology (Oxford, England). 2021 [2]Barnabe C, Feehan L. High-resolution peripheral quantitative computed tomography imaging protocol for metacarpophalangeal joints in inflammatory arthritis: the SPECTRA collaboration. The Journal of rheumatology. 2012;39(7):1494-5 [3]van der Heijde D. How to read radiographs according to the Sharp/van der Heijde method. The Journal of rheumatology. 2000;27(1):261-3 Acknowledgements The Danish Rheumatism Association (R179-A6365-B1668), The Health Research Foundation of Central Denmark Region (R64-A3145-B1504 and R49-A2254-B1504), The Novo Nordic Founda-tion, A.P. Møller Fonden, The Becket fund (20-2-5756), The Aase and Einar Danielsens fund (20-10-0254), The Family Hede Nielsens fund, The Grosserer L.F. Foghts fund and Aarhus University funded this project. The authors would like to thank all study participants and the clinical staff involved in this project. Disclosure of Interests Josephine Therkildsen: None declared, Rasmus Klose-Jensen: None declared, Anne-Birgitte Blavnsfeldt: None declared, Bente Langdahl Speakers bureau: BLL has received honorariums from Amgen, UCB, Eli Lilly, Gedeon-Richter and Astellas., Consultant of: BLL has worked as a consultant for Amgen, UCB, Gedeon-Richter, Eli Lilly and Gedeon., Grant/research support from: BLL has received financial grants from Amgen and the Novo Nordic Foundation., Anna Zejden: None declared, Jesper Thygesen: None declared, Kresten Keller: None declared, Ellen-Margrethe Hauge Speakers bureau: EMH has received honorariums and/or consulting fees from AbbVie, Sanofi, Sobi, and SynACT Pharma., Grant/research support from: EMH has received research grants to Aarhus University Hospital from Danish Regions Medicine Grants, Roche, Novartis, and the Novo Nordic Foundation.